Drafting instrument



E. C. Mc FADDEN DRAFTING INSTRUMENT Filed April 28, 1924 INVENTOR [Zvzrxsov 6 ATTORNEY Patented Aug. 6, 1929.

. 1,123,511] UNITED STATES PATENT OFFICE.

EMERSON e. mcrannnn, or snow HILLS, New JERSEY.

imerrme ms'rxumnnr.

Application filed April 28,

My invention relates to a drafting instrument adapted to provide in a s ngle device a simple and easy means of making sketches and drawings, and of particular advantage in the making of perspective and isometrical perspective views and sketches of various sorts involving or including obhque lines.

The device is preferably made of transparent material, such as celluloid, and the preferred form is illustrated in the accompanying drawing.

Referring to said drawing, the device as a whole is designated by reference character 10 andmay consist of a piece of sheet celluloid or equivalent preferably transparent material. s

The device is preferably in the form of a five sided figure, making up substantially a rectangle so far as three of the sides are concerned, and having the fourth boundary divided into two parts with a reentrant angle between them. In this way, the base or side opposite the fourth boundary can be provided with an ordinary scale, as in. 2 inches, for laying out horizontal, vertlcal, etc.,- distances, and the, upper sides can be arranged at such angles to one another and to the horizontal and with such scales laid out thereon as to keep length, breadth or thickness, and height in suitable proportions to 've a goodperspective view.

' he five sides or edge portions referred 'to are indicated by reference characters 12, 14, 16, 18 and 20'. The base 12 is provided with a scale 12 in standard units, as inches, and is used for measuring or la ing out any parts which are to appear in t e drawing of actual len 'th, as, for example, verti cal distances. he ends 14 and20 may be 4 these scales are not-essential and may be dispensed with,- particularly where the base side 12 is relatlvely long, and may be made use of to measure distances considerably lon er than could be laid out or measured wit the sides 14 and 20."

Side 14 is at aright angle to base 12,.so that when aligned with the edge of the paper it may be usedto keep the instrument 1nposition with the base line 12 erpendicular to the edge of the paper. ide 20 is also referably perpendicular to base linev 12, so t at it may be used in the same we as'side 14, and may also be used in the position shown for drawin vertical lines toward the right hand side 0 the view, or, in

provided with similar scales if desired, but

1924. Serial 1m. 709,488.

reversed position, for drawin vertical lines toward the left hand side of t c View.

. Sides 16 and 18 are formed in such a way as to suitably represent width and length respectively in a perspective or isometric view. In the form shown, side 16 forrepresenting width is inclined downwardly from the vcr tical edge 14 at an angle of about 25 degrees to the base 12, and side 18 for repree senting length is inclined upward towards the edge 20 at an angle of about 7.5 degrees to the base 12,. and the reentrant angle 22 between sides 16 and 18 is about 147.5 degrees, but there may be more or less variation in these angles, which are chosen to give a good perspective representation.

As length and width are foreshortened in perspective views, the scales 16 and 18 are suitably foreshortened. A suitable proportion for scale 16 is on the basis of 2; inch per inch of actual width and for 18 7/ inch /8 per inch of actual length, but here tbo there may be more or less variation, as will be understood.

Provision is also made for guides for maki'n elliptical outlines slanting to right or 1e t or horizontal for drawing lines to represent circles or circular openings or surfaces, and in the form shown, the celluloid material is shown as beingprovided with suitable cutouts for'this purpose.

For this purpose-I have shown adjacent to side 14 the small left slanting elliptical cutout 24 and cutout ellipse parts 24 and 24 surrounding 24 and adapted for making larger ellipses or parts thereof. Adjacent to side. 20 I have shown the provision for making right hand slanting ellipses comprising a relatively small central elliptical cutout 26 and surrounding larger ellipse guide cutouts 26 and 26 respectively. In substantially the central portion of the device I have arranged a guide for making non-slanting ellipses comprising the central elliptical cutout 28 and surrounding partial elliptical cutouts 28 for somewhat larger ellipses.

In laying out angular lines in the oblique portions of views representative of length and breadth, it is desirable to have protractors arranged with their bases on the nee essary slant, and .I, therefore, provide the y ;tw o 'protrac'tors 30 and 32 adjacent-to the sides16 and 18 and having their-bases 34 and 36 parallel to sides 16 and 18 respectively.

It will be seen that the instrument serves as a *aluable guide for laying out sketches and drawings and enables verysatisfactory results to be obtained by users having little or no knowledge of drafting. In making use of the instrument for making isometrical perspective views, the lines representative of width and length are drawn along sides 16 and 18 with side 12 perpendicular to the side edge of the paper, and scales 1(3 and 18 are used to lay off length and width dimensions, and the vertical lines are drawn to scale using full size scale 12? for this purpose. \Vhcre a circle or part thereof is required to be made in the width or length of a View, the elliptical guides of the proper slant are used, correct slant being obtained by keeping the appropriate edge of'the instrument at a right angle to the edge of the paper, as will be'readily understood. In this way representative sketches and drawings can be readily produced with a minimum expenditure of time and trouble, and

the proper angles and lengths are d'eter-' mined in a very simple way and substantially automatically by merely shifting the instrument about in proper relation to the edge of the paper.

I claim:

1. A drafting instrument for making oblique views, comprising a five sidedplate of celluloid or like transparent material, the longer base side thereof being divided into standard scale units, the sides adjacent to the base extending at right angles to the' base, and the boundary opposite the base comprising a part extending inwardly at about 25 degrees to the base and a meeting 7 part intersecting the first part at a reentrant angle of about 147.5 degrees, said parts being provided with iscalcs foreshortened with respect to the standard unit and serving when the base line is horizon-H tal for drawing of lines representative of width and length of objects represented in oblique views.

2. A drafting instrument comprising a plate having a substantially straight base edge serving to determine the position of the instrument when the same is in use andserving as a guide in making certain of the "lines of a perspective view, and edge pertions at the opposite side of said plate serving as guides for making the other-angularly arranged length and breadth lines respectively of said perspective view; said 'opposite edge portions being arranged at different predetermined angles to said base edge and at an an le to each other; and the angles thereof being coordinated to locate said length and breadth lines. in the proper angular relation to each other, and produce a good pers ective view.

3. A dra ting instrument comprising a 'plate having 'a substantially straight base edge provided with calibrations and serving to determine the" position of the instrument when the same is in use and serving as a guide in making certain of the lines of a perspective view, and edge portions at the opposite side ot'said plate serving as guides for making the other angularly arranged length and breadth lines respectively of said perspective view; said opposite edge portions being arranged at ditl'erent predetermined angles to said base edge and at an angle-to each other; and the angles thereot being coordinated to locate said length and breadth lines in the proper angular relation to each other, and produce a good perspective view, and calibrations of said opposite edge portions foreshortened relative to the calibrations on said straight edge and varying in size in accordance with the angularity of said opposite edge portions relative to said straight edge.

4. -A dra t'ting instrument comprising a plate having a substantially straight base edge serving to determine the position of the instrument when the same is in use and serving as a guide in making certain of the lines of a perspective view, and edge portions at theopposite'side of said plate serving as guides for making the other angularly arranged length and breadth lines respectively of said perspective view; said opposite edge portions being arranged at ditl'erent predetermined angles to said base edge and at an angle to each other; and the angles thereof being coordinated to locate said length and breadth lines in the proper angular relation to each other, and produce a good perspective view, and pr'otractors on said plate associated with said opposite edge portions, and each protractor having the base thereof arranged parallel with its respective opposite edge portion.

5. A drafting instrument comprising a plate having a substantially straight base edge serving to determine the position of the instrument when the same is in use and serving as a guide in making certain of the lines of a perspective view, and edge portions at the opposite side of said )late serving as guides for making the ot ier angularly arranged length and breadth lines respectively of said perspective View; said opposite edge portions being arranged at; different predetermined angles to said base edge and at an angle to each other; and the angles thereof being coordinated to locate said length and breadth lines in the proper ltltl Ill) portions of unequal length at the opposite side of said plate serving as guides for making the angularly arranged length and breadth lines of a pers ective view, and directed inwardly towar s said lower edge at difi'erent predetermined angles relative thereto and forming a reentrant angle therebetween;- and the m les thereof being coordinated to locate said length and breadth 'lines in the proper angular relation to each other and produce a good perspective view, and calibrations on said opposite edge portions foreshortened relative to said standard calibrations in accordance with the inclinations of said opposite edge portions relative to said strai t edge. In testimony w ereof, I have signed my name hereto.

EMERSON o; MoFADDEN. 

